diff --git a/internal/repository/postgres.go b/internal/repository/postgres.go
index 3c1e31e..df7523f 100644
--- a/internal/repository/postgres.go
+++ b/internal/repository/postgres.go
@@ -6,7 +6,8 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"sort"
+	"os"
+	"runtime"
 	"strconv"
 	"strings"
 	"time"
@@ -18,6 +19,36 @@ import (
 	"github.com/jackc/pgx/v5/pgxpool"
 )
 
+// #region agent log
+func agentDebugNDJSON3214(hypothesisID, location, message string, data map[string]any) {
+	if os.Getenv("EVOBGP_DEBUG_LOG") != "1" {
+		return
+	}
+	f, err := os.OpenFile("debug-3214dc.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+	var ms runtime.MemStats
+	runtime.ReadMemStats(&ms)
+	payload := map[string]any{
+		"sessionId":    "3214dc",
+		"hypothesisId": hypothesisID,
+		"location":     location,
+		"message":      message,
+		"data":         data,
+		"timestamp":    time.Now().UnixMilli(),
+		"allocBytes":   ms.Alloc,
+	}
+	b, err := json.Marshal(payload)
+	if err != nil {
+		return
+	}
+	_, _ = f.Write(append(b, '\n'))
+}
+
+// #endregion
+
 // Postgres implements store.Backend using pgxpool.
 type Postgres struct {
 	pool *pgxpool.Pool
@@ -42,22 +73,15 @@ func (p *Postgres) DemoIDs() (tenant, moduleCDN, moduleIP, revision, speaker str
 
 func (p *Postgres) MaterializedPrefixStats() (max int, sum int) {
 	ctx := context.Background()
-	rows, err := p.pool.Query(ctx, `
-		SELECT COALESCE((meta_json->>'materialized_prefix_count')::int, 0) AS n
-		FROM config_revision`)
+	// Агрегация в БД — не тащим все строки config_revision в память.
+	err := p.pool.QueryRow(ctx, `
+		SELECT
+			COALESCE(MAX((meta_json->>'materialized_prefix_count')::int), 0),
+			COALESCE(SUM((meta_json->>'materialized_prefix_count')::int), 0)
+		FROM config_revision`).Scan(&max, &sum)
 	if err != nil {
 		return 0, 0
 	}
-	defer rows.Close()
-	for rows.Next() {
-		var n int
-		if rows.Scan(&n) == nil {
-			sum += n
-			if n > max {
-				max = n
-			}
-		}
-	}
 	return max, sum
 }
 
@@ -554,14 +578,29 @@ func (p *Postgres) ListRevisions(tenantID, moduleID string, cursor string, limit
 	if limit <= 0 {
 		limit = 50
 	}
+	off := 0
+	if cursor != "" {
+		if n, err := strconv.Atoi(cursor); err == nil && n >= 0 {
+			off = n
+		}
+	}
 	ctx := context.Background()
-	q := `SELECT id::text, module_id::text, content_hash, parent_revision_id::text, meta_json, created_at FROM config_revision WHERE tenant_id=$1`
+	// List endpoint only needs materialized_prefix_count from meta_json — not full preview_fragments blobs.
+	// LIMIT/OFFSET in SQL avoids loading every revision for the tenant into memory (was O(N) per request).
+	q := `SELECT id::text, module_id::text, content_hash, parent_revision_id::text,
+		COALESCE((meta_json->>'materialized_prefix_count')::int, 0), created_at
+		FROM config_revision WHERE tenant_id=$1`
 	args := []any{tenantID}
+	n := 2
 	if moduleID != "" {
-		q += ` AND module_id = $2`
+		q += fmt.Sprintf(` AND module_id=$%d`, n)
 		args = append(args, moduleID)
+		n++
 	}
 	q += ` ORDER BY created_at DESC`
+	// Fetch limit+1 rows to compute has_more without COUNT(*).
+	q += fmt.Sprintf(` LIMIT $%d OFFSET $%d`, n, n+1)
+	args = append(args, limit+1, off)
 	rows, err := p.pool.Query(ctx, q, args...)
 	if err != nil {
 		return nil, "", false
@@ -572,58 +611,53 @@ func (p *Postgres) ListRevisions(tenantID, moduleID string, cursor string, limit
 		var r store.Revision
 		r.TenantID = tenantID
 		var mod, parent *string
-		var meta []byte
-		if err := rows.Scan(&r.ID, &mod, &r.ContentHash, &parent, &meta, &r.CreatedAt); err != nil {
+		var mpc int
+		if err := rows.Scan(&r.ID, &mod, &r.ContentHash, &parent, &mpc, &r.CreatedAt); err != nil {
 			continue
 		}
 		if mod != nil {
 			r.ModuleID = *mod
 		}
 		r.ParentRevisionID = strOrNil(parent)
-		var mj struct {
-			PreviewFragments        map[string]string `json:"preview_fragments"`
-			MaterializedPrefixCount int               `json:"materialized_prefix_count"`
-		}
-		_ = json.Unmarshal(meta, &mj)
-		if mj.PreviewFragments == nil {
-			mj.PreviewFragments = map[string]string{}
-		}
-		r.PreviewFragments = mj.PreviewFragments
-		r.MaterializedPrefixCount = mj.MaterializedPrefixCount
+		r.MaterializedPrefixCount = mpc
+		r.PreviewFragments = map[string]string{}
 		all = append(all, &r)
 	}
+	agentDebugNDJSON3214("A", "repository/postgres.go:ListRevisions", "list_revisions_fetched", map[string]any{
+		"rows": len(all), "limit": limit, "offset": off,
+	})
+	hasMore := len(all) > limit
+	if hasMore {
+		all = all[:limit]
+	}
+	next := ""
+	if hasMore {
+		next = fmt.Sprintf("%d", off+limit)
+	}
+	if len(all) == 0 {
+		return nil, "", false
+	}
+	return all, next, hasMore
+}
+
+func (p *Postgres) ListRevisionPrefixes(tenantID, revisionID string, cursor string, limit int) ([]store.PrefixRow, string, bool) {
+	if limit <= 0 {
+		limit = 50
+	}
 	off := 0
 	if cursor != "" {
 		if n, err := strconv.Atoi(cursor); err == nil && n >= 0 {
 			off = n
 		}
 	}
-	end := off + limit
-	next := ""
-	hasMore := false
-	if end > len(all) {
-		end = len(all)
-	} else {
-		hasMore = true
-		next = fmt.Sprintf("%d", end)
-	}
-	if off >= len(all) {
-		return nil, "", false
-	}
-	return all[off:end], next, hasMore
-}
-
-func (p *Postgres) ListRevisionPrefixes(tenantID, revisionID string, cursor string, limit int) ([]store.PrefixRow, string, bool) {
-	if limit <= 0 {
-		limit = 50
-	}
 	ctx := context.Background()
 	if _, err := p.GetRevision(tenantID, revisionID); err != nil {
 		return nil, "", false
 	}
 	rows, err := p.pool.Query(ctx, `
 		SELECT prefix::text, community_id::text, source FROM revision_materialized_prefix
-		WHERE revision_id=$1 ORDER BY id`, revisionID)
+		WHERE revision_id=$1 ORDER BY id
+		LIMIT $2 OFFSET $3`, revisionID, limit+1, off)
 	if err != nil {
 		return nil, "", false
 	}
@@ -638,25 +672,21 @@ func (p *Postgres) ListRevisionPrefixes(tenantID, revisionID string, cursor stri
 		pr.CommunityID = comm
 		all = append(all, pr)
 	}
-	off := 0
-	if cursor != "" {
-		if n, err := strconv.Atoi(cursor); err == nil && n >= 0 {
-			off = n
-		}
+	agentDebugNDJSON3214("B", "repository/postgres.go:ListRevisionPrefixes", "list_prefixes_fetched", map[string]any{
+		"rows": len(all), "limit": limit, "offset": off,
+	})
+	more := len(all) > limit
+	if more {
+		all = all[:limit]
 	}
-	end := off + limit
 	next := ""
-	more := false
-	if end > len(all) {
-		end = len(all)
-	} else {
-		more = true
-		next = fmt.Sprintf("%d", end)
+	if more {
+		next = fmt.Sprintf("%d", off+limit)
 	}
-	if off >= len(all) {
+	if len(all) == 0 {
 		return nil, "", false
 	}
-	return all[off:end], next, more
+	return all, next, more
 }
 
 func (p *Postgres) CreateRollbackRevision(tenantID, sourceRevisionID string) (string, error) {
@@ -697,32 +727,54 @@ func (p *Postgres) RevisionDiff(tenantID, aID, bID string) (map[string]any, erro
 	if _, err := p.GetRevision(tenantID, bID); err != nil {
 		return nil, err
 	}
-	pa, _, _ := p.ListRevisionPrefixes(tenantID, aID, "", 100000)
-	pb, _, _ := p.ListRevisionPrefixes(tenantID, bID, "", 100000)
-	setA := make(map[string]struct{})
-	setB := make(map[string]struct{})
-	for _, x := range pa {
-		setA[x.Prefix] = struct{}{}
+	ctx := context.Background()
+	var unchanged int
+	err := p.pool.QueryRow(ctx, `
+		SELECT COUNT(*)::int FROM (
+			SELECT prefix FROM revision_materialized_prefix WHERE revision_id=$1::uuid
+			INTERSECT
+			SELECT prefix FROM revision_materialized_prefix WHERE revision_id=$2::uuid
+		) t`, aID, bID).Scan(&unchanged)
+	if err != nil {
+		return nil, err
 	}
-	for _, x := range pb {
-		setB[x.Prefix] = struct{}{}
+	// added: в B, нет в A; removed: в A, нет в B — без загрузки полных снапшотов в память.
+	rowsAdded, err := p.pool.Query(ctx, `
+		SELECT prefix::text FROM (
+			SELECT prefix FROM revision_materialized_prefix WHERE revision_id=$1::uuid
+			EXCEPT
+			SELECT prefix FROM revision_materialized_prefix WHERE revision_id=$2::uuid
+		) s ORDER BY 1`, bID, aID)
+	if err != nil {
+		return nil, err
 	}
-	var added, removed []string
-	unchanged := 0
-	for pfx := range setB {
-		if _, ok := setA[pfx]; !ok {
-			added = append(added, pfx)
-		} else {
-			unchanged++
+	defer rowsAdded.Close()
+	var added []string
+	for rowsAdded.Next() {
+		var s string
+		if err := rowsAdded.Scan(&s); err != nil {
+			continue
 		}
+		added = append(added, s)
 	}
-	for pfx := range setA {
-		if _, ok := setB[pfx]; !ok {
-			removed = append(removed, pfx)
+	rowsRem, err := p.pool.Query(ctx, `
+		SELECT prefix::text FROM (
+			SELECT prefix FROM revision_materialized_prefix WHERE revision_id=$1::uuid
+			EXCEPT
+			SELECT prefix FROM revision_materialized_prefix WHERE revision_id=$2::uuid
+		) s ORDER BY 1`, aID, bID)
+	if err != nil {
+		return nil, err
+	}
+	defer rowsRem.Close()
+	var removed []string
+	for rowsRem.Next() {
+		var s string
+		if err := rowsRem.Scan(&s); err != nil {
+			continue
 		}
+		removed = append(removed, s)
 	}
-	sort.Strings(added)
-	sort.Strings(removed)
 	return map[string]any{
 		"revision_a": aID,
 		"revision_b": bID,